1. Field of the Invention
The present invention relates to an optical component which is used for optical transmission, and more particularly, to an optical component formed by combining an optical attenuator and an isolator, the optical component used as a module.
2. Description of the Related Art
In an optical network, many cases, particularly, a wavelength division multiplexing (WDM) system, use an optical attenuator to equalize optical power. However, when the optical attenuator is used, back reflection may cause a problem. Thus, an isolator is installed to the rear of the attenuator to prevent generation of this problem.
However, the use of an isolator causes several undesirable effects such as additional insertion loss, complexity of the device due to use of additional components, and an increase in the cost due to additional material.
Upon establishment of an optical network, when an optical attenuator and an isolator are connected to each other in series, insertion loss that is the sum of the insertion losses of the two optical devices, is generated. In particular, an optical add drop multiplexer requires as many optical attenuators and isolators as the number of channels, thus increasing the total size of the apparatus.
Also, when an optical attenuator is used without isolators, the back reflection of the optical attenuator is highly likely to cause problems in optical signal transmission.